1. Field of the Invention
The present invention relates to a method of forming a resist pattern on a semiconductor base, the pattern having predetermined dimensions and a profile, a method of manufacturing a semiconductor device using this method of forming a resist pattern, a device and a hot plate for forming a resist pattern.
2. Discussion of Background
In manufacturing a semiconductor device, a pattern is formed by patterning a resist on an oxide film, being an etched film, such as a polysilicon film, and a metallic film, and by etching using this resist as a mask. However, in accordance with recent microminiaturization of this pattern, a resist pattern is formed by providing an anti-reflective coating for obtaining a high accuracy in controlling dimensions and maintaining a resist profile on the etched film.
As such an anti-reflective coating, an inorganic anti-reflective coating, for example, a silicon nitride (Si.sub.3 N.sub.4) film, a silicon oxynitride (SiON) film, and a titanium nitride (TiN) film and an organic anti-reflective coating of a coating type are used. However, the anti-reflective coating having an inorganic base is required to be careful so as not to be harmful to a device function in a case that it is left in a semiconductor device as a final product. Also, it is difficult to establish a stable removing process in a case that such an anti-reflection film is removed. As described, it is difficult to use the anti-reflective coating having the inorganic base, and the anti-reflective coating having the organic base is advantageous because of its easy removal after photolithographing.
However, the above-mentioned conventional method of forming the resist pattern and so on had problems that pattern defects were caused, a shape of resist pattern was deteriorated, and dimensions of resist were instabilized because a surface condition of the organic base is differed by characteristics of its material, a density of the film, and so on, and therefore a resist film on an upper layer of the organic base was influenced by the surface conditions when the resist pattern was formed on the organic layer.
Such phenomenons were conspicuous when a chemically amplified resist, sensitive to an atmosphere of resist film, was used, whereby a big problem was caused when the resist, currently being a main stream of a resist for microminiaturization, was used.
In case of a positive resist, the chemically amplified resist is mainly composed of a resin obtained by bonding molecules (dissolution inhibition function group) for restricting a solubility to a portion inherently depressing a high solubility in a developing solution and a photo acid generator, wherein the resist is not dissolved in the developing solution in an unexposed portions because a reaction caused by an exposure does not proceed, and acids are generated from the acid generator by a photoreaction in an exposed portion, whereby these acids facilitate a thermal deprotection reaction of dissolution inhibition function group in the resin and finally a reaction of the resin solubilized in the developing solution.
There were problems that, in a case that materials exhibiting acid were contained in an under layer film, an deprotection reaction was abnormally proceeded because acidic materials promoted a deprotection reaction of the dissolution inhibition function group in the resist. On the other hand, there were problems that, in a case that basic materials were contained in the under layer film, acids generated during resist process were nutrized by these basic materials so as not to contribute the deprotection of the dissolution inhibition function group, and so on.